1. Field of the Invention
This invention relates to surgical instrumentation and more particularly to an instrument for use with an image-directed apparatus to perform an excisional biopsy, for example, of a lesion in a patient""s breast. The invention and associated method relate to a manner in which biopsy tissue may be excised and extracted through a minimally invasive incision.
2. Description of Prior Art
It often is necessary to biopsy tissue from the interior of the body for diagnostic purposes. For example, when a physician discovers a suspicious breast lesion, a biopsy typically is performed on a small tissue sample to determine whether to remove the lesion or to perform another more invasive surgery. It remains common practice to use an open surgical approach to recover a tissue sample for biopsy purposes. Such an open excisional biopsy causes trauma and may leave undesirable scarring.
In many cases, a needle biopsy approach is employed. A xe2x80x9cfine needle aspirationxe2x80x9d approach utilizes a hollow 22 gauge needle wherein a small amount of tissue may be aspirated into the needle bore which then may be biopsied. Alternatively, a small core of tissue may be sampled with a xe2x80x9ctrue-cutxe2x80x9d or xe2x80x9cquick-cutxe2x80x9d needle in which an 18 gauge hollow needle with a sharpened tip reciprocates over a notched stylet. The elongate notch in the stylet collects a tissue core for biopsy purposes. Such needle-biopsy approaches cause little trauma but suffer from the disadvantage of recovering a only a small amount of tissue for biopsy purposes.
A recently developed approach is called a xe2x80x9clarge-corexe2x80x9d stereotactic needle biopsy in which a 14 gauge hollow needle is employed together with an image-directed technology for digitally localizing the biopsy needle in relation to a breast lesion. To utilize the stereotactic needle apparatus, the patient lays prone on an operating platform that exposes and holds the breast in a stationary position below the platform. An x-ray stereo imaging unit is mounted below the platform and displays a stereo image of the lesion on a video monitor. A xe2x80x9clarge-corexe2x80x9d needle assembly is mounted on a traveling arm below the platform and may be positioned in three axes by digital coordination with the stereo x-ray images. The large-core needle employs a 14 gauge hollow needle that reciprocates over a notched stylet similar to above-described xe2x80x9ctrue-cutxe2x80x9d needle. After the needle tip is digitally positioned just outside the breast, a double spring-loaded needle first projects the stylet through the lesion and then instantly projects the needle over the notched stylet to excise tissue within the notch in the stylet. The principal advantage of the stereotactic needle biopsy over other needle biopsy approaches is that the image-directed apparatus insures that tissue is excised from the exact site of the lesion. The 14 gauge needle also recovers a larger tissue sample than other needle biopsy approaches. Also, such a stereotactic needle biopsy causes little trauma because of the small diameter of the needle.
The stereotactic needle approach still does not recover a large tissue sample. Even in repeated cycles of insertion and withdrawal, 5 to 6 cycles being typical, the 14 gauge stereotactic needle can excise and extract only a small portion of a suspect lesion. In contrast, in an open excisional biopsy, the entire lesion may be removed. There is therefore a need for new instruments and methods for excising and extracting biopsy tissue from the interior of the body through a minimally invasive incision, and particularly for performing an excisional biopsy on a breast lesion through a needle incision utilizing a stereo image-directed apparatus to digitally localize the excision.
In general, the instrument and method in accordance with the present invention are utilized to excise and extract tissue from the interior of the body through a minimally invasive needle incision. The instrument is adapted for use with a stereotactic needle apparatus to precisely direct the tip of the needle assembly to the site of the lesion.
The instrument incorporates a disposable flex-blade needle cutter including:
(a) a hollow sleeve with a needle tip incorporating flexible rotatable blades that are movable between a first position in which the blades are contracted relative to the needle shaft for piercing into a patient""s body and a second position in which the flexors are expanded in an arc outward relative to the needle shaft for excising tissue,
(b) a blade-flexing mechanism for flexing the blades between the first and second positions;
(c) a rotation mechanism for rotating the flexors;
(d) an infusion channel within the hollow sleeve for supplying saline solution to the region of the flexors;
(e) an aspiration channel associated with the flexors for extracting fluids and excised tissue; and
(f) a needle insertion mechanism for piercing the needle tip into tissue.
In using the flex-blade needle to remove a breast lesion, the surgeon locks the needle in an actuator incorporating actuation mechanisms, including a blade flexing mechanism, a blade rotation mechanism, a needle insertion mechanism, a saline infusion source and an aspiration source. The patient is positioned on a stereotactic needle apparatus. The actuator body then is fitted to the traveling arm of the stereotactic needle apparatus. The physician employs conventional digital imaging technology to direct the tip of the needle to the correct xe2x80x9cxxe2x80x9d, xe2x80x9cyxe2x80x9d and xe2x80x9czxe2x80x9d coordinates just exterior to the skin of the breast. The surgeon then selects a pre-programmed actuation cycle on a controller for the particular diameter of the needle and the dimensions of the tissue to be excised and extracted. The controller in sequence advances the needle tip with the flexors in the contracted position into the breast to the site of the lesion and then rotates and simultaneously flexes the flexors to the expanded position from the contracted position, thus incising tissue. At the same time, saline solution is infused into the region of the rotating flexors through the infusion channel while an aspiration source aspirates the excised tissue mixed with the saline through the separate aspiration channel. The extracted tissue is collected in a filter in a tissue-sampler. The controller then automatically returns the flexors to the contracted position and withdraws the needle from the breast.
In general, the present invention provides an instrument and method for excising and extracting tissue from the interior of the body (not just the breast) through a small diameter needle. The transverse sectional dimension of the excised tissue is advantageously large in relation to sectional dimension of needle shaft through which the tissue is extracted.
The present invention provides an instrument and method that cooperates with a stereotactic needle apparatus to digitally localize the excisional biopsy.